Millions of people love Twitter because it’s a great way to share information and socialise. So folks in Twitterland really hate the old hard-sell ‘buy my product’ type messages. Companies that try to use traditional sales and advertising ploys in social media usually get slapped down pretty quickly.

So when Twitter announced this week that it is clamping down on would-be advertising platforms, you would think that you’d be hearing cheers from across the twittosphere. Instead, there was a collective intake of breath and then quiet, in anticipation of the next announcement.

Twitter’s blog said, “We will not allow any third party to inject paid tweets into a timeline on any service that leverages the Twitter API.” This could spell doom for services like Magpie and Tweetup. Magpie boasts that it’s the original Twitter advertising network. It claims to assist brands in harnessing sponsored conversations via mutually beneficial partnerships between advertisers and twitteri. Tweetup uses much the same model as PPC search engine advertising, giving priority to ‘high quality tweets’ in its search platform.

But one has to wonder why, when the likes of Magpie and Tweetup have been trundling along steadily growing business for quite some time, that Twitter has now decided to call a halt to it all? Perhaps it’s because Biz and his team have got something similar up their own sleeves and want to pre-empt the competition?

The microblogging service has already announced a new ‘promoted tweets’ function that will see advertisers pay to have their Twitter updates highlighted in searches; Best Buy, Bravo, Red Bull, Sony Pictures, Starbucks, and Virgin America are all said to among the first brands to sign up for the service.

So will the community tolerate this commercialisation of Twitter or will there be a huge backlash that puts the advertisers’ brands at risk? My guess is that the community will bear it rather well.

We tweeps want Twitter to find a viable business model to ensure it remains a going concern and at the same time, we’re unlikely to actually want to pay to use the service ourselves. So putting up with a few search ads seems a rather small price to pay when you consider all the benefits to Twitter that we enjoy.

And, promoted tweets are likely to be the thin end of the wedge. As brands get to grips with social media generally along with specific platforms such as Twitter and location-based services Foursquare and Gowalla, we’ll be seeing a much higher volume of ‘commercial messages’ as integral parts of the conversation.